HP PSC 1400 - How can i over ride the system to accept compatible cartridges?

I have an HP PSC 1400 series printer and I have always used compatible inks. I have put in a new ink (exactly the same as the one I took out and from the same manufacturer) and it keeps coming up with the message that this is the wrong ink cartridge. How can I over ride this and use the cartridge?

Thanks to anyone who has already commented but unfortunately I am not able to buy a new printer at the moment.

Many thanks for any help you can give me.

Debs x